As an afterthought, gaming puts a PC's components into overdrive more than any other application, and running the most recent(and future) state-of-the-art games at decent frame rates with above minimum settings requires a powerful system.
So if you're a serious gamer, or plan to become one, then you have 2 options:
1- Upgrade most of your existing system's components.
2- Buy a dedicated gaming system.
And since both require spending some serious $, I suggest going with option 2. I've already done option 1, and it did not go smoothly at all, e.g., defective components had to be returned for replacements(I paid for the shipping), drivers sometimes did not load properly, the O/S had to be reinstalled, etc.